1. Field of The Invention
The present invention relates to a microwave oven, and more particularly, to a microwave oven having a microwave detecting device for detecting an operational status of a magnetron by detecting a microwave within a waveguide.
2. Description of The Prior Art
FIG. 1 is a partially cross-sectioned perspective view of a conventional microwave oven. As shown in FIG. 1, a door 4 is pivotedly fixed on one side of a body 1 to open/close a cooking chamber 2. A rotary plate 5 is arranged on the bottom of the cooking chamber 2, and food to be cooked is placed on the rotary plate 5. The reference numeral 7 refers to a control panel, i.e., a button inputting section, 8 is an air guide, and 9 is a cooling fan. A magnetron MGT is disposed in a device chamber 3. Accordingly, the air from the cooling fan 9 cools the device chamber 3, while being guided into the device chamber 3 through an air guide 8. The control panel 7 is formed on the front side of the device chamber 3. A user controls the operations of the microwave oven though various buttons of the control panel 7. Generally, the control panel 7 has a display 7A. The display 7A displays data from the button input section 7, the operational status of the microwave oven, and messages, etc.
FIG. 2 is a view for schematically showing a microwave detecting device of a conventional microwave oven. In FIG. 2, the reference character D refers to a diode sensor, and reference numeral 10 refers to a waveguide, 100 is a microwave detecting device, 120 is a shield member, and 130 is a microcomputer.
FIG. 3 is a circuit diagram of a microwave detecting section disposed in the waveguide of FIG. 2. As shown in FIG. 3, in the microwave detecting section 100, electric current produced by the electric field from a loop antenna 101 is detected through the diode sensor D, and a capacitor C is charged/discharged. Here, a certain voltage is outputted across a resistor R. A Zener diode ZD is used to prevent the voltage from being overly outputted.
The microwave detecting device of the conventional microwave oven has the shortcoming that it can not detect abnormal operation of the microwave oven, which is caused due to the non-oscillation of the magnetron MGT.
Further, the microwave detecting device of the conventional microwave oven can not detect the malfunction of the microwave oven, which is caused due to the breakage of the diode sensor D.